Yang Zhu 楊朱 was a philosopher of the Warring States period (5th cent.-221 BCE) and the founder of a schools of thinkers called the Yangist school (Yang Zhu xuepai 楊朱學派). He hailed from the state of Wei 魏 and is known with the epithet Yangzi 楊子, Yinzi Ju 陰子居 or simply Master Yin 陰生.

The dates of his life are not known, but his school flourished during the time of the Confucian philosopher Meng Ke 孟軻 (Mengzi 孟子). Together with the Mohists, the Yangist school was apparently the most prevalent among the philosophical schools of that time.

There are no books known to have been written by a representant of the Yangist school. All what is known about their teachings are quotations in books like the Mengzi 孟子, Zhuangzi 莊子, Hanfeizi 韓非子, Lüshi chunqiu 呂氏春秋, Huainanzi 淮南子 or Liezi 列子. Part of them, especially the Mengzi, is extremely critical towards Yang Zhu. The Liezi contains a whole chapter about Yang Zhu and his teachings, but this chapter seems to be a later forgery.

Yang Zhu is often called a "hedonist" or "egoist" because his philosophy is centered on the self. The own life is more valid than that of any other person. In order to gain satisfaction and harmony one has to make oneself free of compassion towards others. Any interaction would positively or negatively change the life of others and thus be harmful. The suffering of the other would only bring myself harm. A famous statement by Meng Ke is that Yang Zhu would not even pull out a single hair of his to save the world.

According to Han Fei, Yang Zhu would never do something that would bring profit to the whole society or the whole state. The book Huainanzi says that Yang Zhu stressed that one had to conserve one's own natural and true character without submitting it to social restrictions.

With such an attitude, Yang Zhu represented an opposite stance towards society than Confucians and the Mohists who advocated a proper etiquette towards others and universal love, respectively. The human nature would be, according to the chapter Yang Zhu in the Liezi, be disturbed by longing for a long life, fame, eminent position and by money. Fame, a "false and vain name" (ming 名) would hide the actual personality, a high position would force its owner to labouriously spend the day instead of enjoying life. A long life would bring ever more unfulfillable wishes and desires. Such thoughts in Yang Zhu's thinking show a tendency towards Daoism.

Yang Zhu is often criticized for the search for the own profit and the complete fulfilment of one's own wishes at the cost of others. If this is right or not, remains doubtful. From the political aspect, Yang Zhu can also be compared with the Daoists because the existence of a state was irrelevant to him. The same is true for his interpretation of Heaven. Afterlife and fate do not play any role in his thinking.